Method fade

content_scripts/hud.js:240–262

(toAlpha, duration, onComplete)

  }

  fade(toAlpha, duration, onComplete) {
    clearInterval(this.intervalId);
    const startTime = (new Date()).getTime();
    const fromAlpha = this.opacity;
    const alphaStep = toAlpha - fromAlpha;

    const performStep = () => {
      const elapsed = (new Date()).getTime() - startTime;
      if (elapsed >= duration) {
        clearInterval(this.intervalId);
        this.updateStyle(toAlpha);
        if (onComplete) {
          onComplete();
        }
      } else {
        const value = ((elapsed / duration) * alphaStep) + fromAlpha;
        this.updateStyle(value);
      }
    };

    this.updateStyle(this.opacity);
    this.intervalId = setInterval(performStep, 50);
  }

  stop() {
    clearInterval(this.intervalId);